1. Field of the Invention
The invention relates to an attenuator, and more particularly to a variable attenuator.
2. Description of the Related Art
In the family of electronic components, the variable attenuator is one of the common and basic components in electrical circuits and systems. The existence of a variable attenuator makes the fabrication of electrical circuits and the debugging of systems more flexible and convenient. Currently, the variable attenuator is being widely used in circuits and systems with operating frequencies below a few hundred megahertz (MHz).
However, there are several problems with the existing variable attenuator: first, the variation of attenuation is implemented by switching a main signal circuit, and a strong reflection signal (a burst pulse) may occur on the main signal circuit and damage a power tube of a previous stage during the switching process; moreover, the attenuator cannot be completely separated from the main signal circuit, and thus variation of attenuation is not easily implemented.